Complete the statement using the most appropriate option:’Did you phone Ruth?’ ‘Oh no, I forgot. _________________.’

The correct answer is: A. I’ll phone in the evening.

The speaker is apologizing for forgetting to phone Ruth, and they are making a promise to phone her in the evening. This is the most appropriate option because it is the most polite and considerate way to respond to the situation.

Option B, I have phoned in the evening, is not correct because the speaker has not yet phoned Ruth. Option C, I phoned in the evening, is also not correct because the speaker is talking about the future, not the past. Option D, I have been phoning in the evening, is not correct because the speaker is only planning to phone Ruth once.